Microsoft Corp. (NASDAQ:MSFT), the No. 1 software company, is completing one of its biggest-ever security updates to respond to major threats to its browsers and users of Office products.The Redmond, Wash., company next week said it plans to publish 12 separate security updates to patch 57 vulnerabilities in Windows, Internet Explorer (IE) browser, Office and Exchange Server software that handles email for enterprises.

Five of the updates will be labeled “critical,” Microsoft's top ranking for danger, while the others will be marked “important.”

Besides updates for older versions of Internet Explorer, the company plans to issue one for the latest one, version 10. Others will cover IE versions 6 through 9.

The updates will also include versions of the new RT software for tablets, including the Microsoft Surface and those made by competitors.

The company plans an extensive briefing on the new updates on Wednesday.

The company said it had learned of vulnerabilities in the Flash Player software developed by Adobe Systems Corp. (NASDAQ:ADBE), which has been used “in targeted attacks” designed to trick users into opening a Microsoft Word document delivered as an email document that contains malicious flash content.

Adobe said separately it's aware that hackers have used Flash player to attack other browsers, including Firefox and Safari, from Apple Inc. (NASDAQ:AAPL), the most valuable technology company.

As a result, Adobe, based in San Jose, Calif., is encouraging users to update their software.

Microsoft didn't advise when it discovered the vulnerabilities but the move comes in a month when the U.S. Federal Reserve Board acknowledged its computer networks were victim of a cyberattack last week and several major banks said they had problems.

In his farewell speech, Secretary of Defense Leon Panetta on Wednesday warned of cyberattacks, which he said are “a growing threat to our economy and a growing threat to our critical infrastracture.”

Panetta, who raised concern about a “cyber Peal Harbor” last year, warned again that cyberattacks can now “cripple a country, take down our power grid system, take down our government system, take down our financial system and literally paralyze the country.”

The Pentagon announced plans to boost its cyber command force to about 5,000 from only 900 professionals now. Panetta urged Congress to do more.

Shares of Microsoft rose 27 cents to $27.55 in Friday trading. With dividends included, they've lost 7 percent over the past 52 weeks.